LIQUEFACTION

1. ANTILIQUEFACTION
MEASURES

2. ANTILIQUEFACTION
MEASURES
 To prevent liquefaction
 Suggested by Lew,1984

3. METHODS
 Compaction of loose sands
 Rolling with rubber tyre rollers
 Compaction with vibratory plates and
vibratory rollers
 Driving of piles
 Vibrofloatation
 Blasting

4.  Grouting and chemical stabilization
 Application of surcharge
 Drainage using coarse material blanket and
drains

5. 1. Compaction of loose sands
 Loose saturated are more prone to liquefaction
than dense saturated sands
 Reduced by compacting loose sand deposits.
 Various methods are as follows…….

6. Compaction of loose sand

7. a. Rolling with rubber tyre rollers
 Excavating some depth
 Carefully backfilling
 Compact soil
 Can not used for compacting deep sand deposits

8. Rolling with rubber tyre rollers

9. b. Compaction with vibratory plates
and vibratory rollers
 Using smooth wheel rollers with vibratory
device inside
 Suggested by Bowles in 1982
 Compacting depth about 1.5m to 2m
 Can not be used for large depth

10. Vibratory plate compacters work well for
compacting granular soils.

11. c. Driving of piles
 Piles driven in loose deposits
 Piles remains in sand , the overall stiffness of
soil stratum increases.

12. Driving of piles

13. Driving of piles

14. d. Vibrofloatation
 Used to densify cohesionless deposits of sand
and gravel
 Equipment about 4m long and 400mm in
diameter.

15. Vibrofloatation

16. e. Blasting
 Explosion of buried charges induces liquefaction
of the soil mass
 Escape of excess pore water pressure
 To facilitate re-arrangement of particle
 To lead more compacted state

17. Blasting

18. 2. GROUTING AND CHEMICAL
STABILIZATION
 Inserting stabilizing agent in to the soil mass
under pressures
 Agents reacts the soil to form a stable mass
 Grout is a mixture of cement and water with or
without sand

19. Grouting and chemical stabilization

20. 3. APPLICATION OF
SURCHARGE
 Effective measure against liquefaction
 Pore pressure increases with increase in
overburden pressure till the maximum value of
pore pressure is reached

21. Application of surcharge

22. 4. DRAINAGE USING COARSE
MATERIAL BLANKET AND
DRAINS
 Higher permeability reduces the length of
drainage path
 Higher coefficient of permeability , speed up the
drainage process.

23. Drains

24. THANK YOU…….